Zygote Arrest Protein 1 (ZAR1)

The female gamete, the oocyte, serves the distinct purpose of transmitting the maternal genome and other maternal factors critical for postovulation events. Oocytes have diverse functions in ovarian folliculogenesis, fertilization, and embryogenesis.

ZAR1 is an oocyte-specific gene that appears to function at the oocyte-to-gamete transition.The mouse and human ZAR1 proteins contain 361 and 424 amino acids, respectively, and share 59% amino acid identity. Both have an atypical PHD motif in their C termini. RT-PCR and Northern blot analysis of mouse tissues detected expression only in ovary. In situ hybridization analysis showed high levels of Zar1 in growing oocytes of ovaries from wildtype mice and from mice lacking growth/differentiation factor-9 (GDF9).